The present invention relates to counters for counting one or more articles arranged in a stack. More particularly, the present invention relates to a counter for counting discs of the type including compact discs (cds) and dvds arranged on a spindle.
Compact discs are frequently handled in large volumes, this is especially true for manufacturers and distributers of compact discs. Correct counts are important to insure customer orders are filled accurately, where shipping too few discs can often result in unhappy customers, and shipping too many discs will often unnecessarily eat into the profits of the manufacturer or distributer. When the volumes become large it becomes ever increasingly more inefficient to manually count the discs. Correspondingly accurate and efficient means for counting a stack of compact discs is desirable.
In the past, various techniques have been tried including simply measuring the height of a stack of discs. In other instances manufacturers have weighed the stack of discs. By knowing the unit height or the unit weight, manufacturers previously attempted to compute the total number of units, based upon the total weight or the total height of the stack of discs. However when compact discs or dvds are manufactured they are allowed a degree of variance within predetermined tolerances. These variances can sometimes make the methods of weighing or measuring the height of the stack somewhat suspect. Furthermore such techniques require that the characteristics of the spindle be taken into account. Consequently more accurate techniques are desirable.
Other previous counters have been developed, two examples of which are described in U.S. Pat. No. 4,994,666 and U.S. Pat. No. 5,315,107, which have taken advantage of an inherent physical feature associated with stacks of discs. When stored, discs generally provide a spacing between each adjacent pair of stacked discs. The spacing or gap is caused by a raised ridge near the center or hub of the disc, sometimes referred to as a boss. The ridge generally extends above the planar surface of the disc on at least one of the sides of the disc. These previous counters use an illuminated source of light having a path, which travels in a direction substantially parallel to the surface of the discs. The previous counters then attempt to detect the light that exits on the other side of the stack of discs. The source of light and the device used to detect the light are then moved relative to the stack of the disc, wherein the path of light is selectively interrupted when the light is received by the stack of discs proximate the edge of a disc, and is allowed to propagate through the discs when the light is received by the stack of discs proximate the gap or spacing between the discs.
These devices are generally larger than the stack of discs and are typically fixed in place. It is generally necessary to bring the discs to be counted to these counter devices and for the stack of discs to be loaded into the machines. For convenience sake it would be beneficial to develop a portable device that could be brought to the discs without sacrificing the accuracy of the counter.
Furthermore, to the extent that the accuracy of the count could be further enhanced, or to the extent that the counter could detect potential problems or errors, such a counter would be further beneficial.
The present invention provides a portable counter for counting one or more articles arranged in a stack. The portable counter comprises a housing, a radiation source, a radiation detector, one or more motors, and a processor.
The housing is sized to be hand carried, the housing having a handle, and a scan surface for facing toward and placing adjacent to the stack of one or more articles to be counted.
The radiation source is oriented so as to produce radiant energy which radiates in a direction toward the stack of articles positioned adjacent to the scan surface. The radiation detector is spaced apart from and oriented toward the radiation source so as to selectively receive radiant energy from the radiation source and produce a corresponding output signal when the direct path between the radiation source and the radiation detector is unobstructed. The direct path between the radiation source and the radiation detector crosses the space, where the stack of one or more articles to be counted is located.
One or more motors are coupled to the radiation source and the radiation detector for moving both the radiation source and radiation detector along the length of the scan surface and the stacked articles positioned adjacent thereto. As the radiation source and the radiation detector move relative to the adjacent stack of articles the direct path between the radiation source and the radiation detector alternatively passes through the one or more articles and the gaps on either side of the one or more articles. The direct path is obstructed when the path passes through one of the articles.
A processor is coupled to receive the output signal of the radiation detector, and includes a counting module for determining the number of articles intersected by the direct path between the radiation source and the radiation detector, as the radiation source and the radiation detector travel along the scan surface of the housing and the height of the stack of articles positioned adjacent thereto.
In at least a further embodiment the processor further includes a distance tracking module for determining the overall height of the stack of articles, and an error checking module for comparing the number of articles intersected as determined by the counting module with the number of discs corresponding to the overall height of the stack of articles as determined by the distance tracking module.
In at least a still further embodiment the counting module determines a count based upon at least two passes of the radiation source and radiation detector respective to the stack of articles, and in at least two different directions.
The present invention further provides a method for counting one or more articles arranged in a stack. Specifically the method includes radiating energy from a radiation source in a direction nearly parallel to the one or more substantially planar surfaces of the articles being counted, and moving the radiation source along the height of the stack of articles, while generally maintaining the direction the energy is being radiated.
The radiated energy is selectively received at a radiation detector, which moves in conjunction with the radiation source, when the direct path between the radiation source and the radiation detector is not obstructed by the one or more articles being counted. The number of articles intersected by the direct path is determined, while the radiation source and the radiation detector traverse the height of the stack of articles. Additionally, the overall height of the stack of articles is determined.
After determining the number of articles intersected and the overall height of the stack of articles, a comparison is made between the determined number of articles intersected and a number of articles consistent with the determined overall height of the stack of articles for detecting any inconsistencies or errors. A count corresponding to the number of articles, and any inconsistencies or errors is then displayed.
By making multiple different types of measurements and comparing the results, the chances of detecting and reconciling an error is significantly improved.
These and other objects, features, and advantages of this invention are evident from the following description of a preferred embodiment of this invention, with reference to the accompanying drawings.